It is believed that the pertinent state-of-the-art is represented by: U.S. Pat. Nos. 1,570,099, 4,420,282, 2,956,674, 2,591,351, 5,112,083 and 4,244,069; GB patent Ser. No. 2377670; Japanese patent/application Ser. No. 2005289422, 3091353U and 58166479U as well as by international patent applications having publication No. WO2007097890.
GB2377670 discloses a notepad using two glues to hold the pages together, the first being a weak adhesive, possibly polyvinyl acetate, to hold the pages together as a bundle and a second very high bond pressure sensitive adhesive, e.g. acrylic, on both sides of a strip of a foam, in the form of a tape, that holds the bundle to the foam and the foam to the spine of the covers. This combination of spine, foam, and two adhesives allows the individual pages to be removed with less tearing of the edges and without the notebook falling apart.
U.S. Pat. No. 5,112,083 discloses a paper pad securement clip for use with a paper pad having a plurality of paper sheet members and optionally including a backing member. The paper pad of U.S. Pat. No. 5,112,083 presents a base surface and an upper surface with the individual sheet members edge glued together. The paper securement clip of U.S. Pat. No. 5,112,083 has a base member secured with respect to the lower end and an upper member secured with respect to the upper end. The base member includes a base member end and a first obliquely angled tip member. A first abutment surface is defined thereon also. The upper member defines an upper member end and a second obliquely angled tip having a second abutment surface. The first and second abutment surfaces are operative to secure the individual paper sheet members of the paper pad together with respect to one another and facilitate removal of individual sheets therefrom. The pad securement device optionally includes a removal arm extending outwardly therefrom defining a cutting edge thereon. A display area may also be defined on the upper surface of the upper member of the pad securement clip to facilitate display of appropriate information thereon.
Use of certain types of adhesives is known in the art in the context of binding sheets. It is noted however that adhesives can be classified into hardening and non-hardening types. Hardening adhesives are typically either reactive adhesives that chemically react to harden, e.g. epoxy glues, adhesives that harden by drying, such as various volatile solvent based adhesives, or thermoplastic adhesives, such as hot melt adhesive (HMA). The common to hardening adhesives is their tendency to undergo a reaction, whether chemical or physical, whether reversible or not, whereby their physical state is altered as they harden and lose their resiliency. Frequently upon hardening such adhesives loose their adhesive properties, towards new objects, which haven't previously engaged to the adhesive.
The use of hardening types of adhesives is known in the art in the context of binding sheets. The use of non-hardening types of adhesives however is very non-common and even contra-intuitive in the context of binding sheets, since the binding force of non-hardening adhesives is typically week to effectively bind the block together whilst their residues on the sheets are further considered as suboptimal for many applications.
U.S. Pat. No. 2,956,674 discloses a binding for flat articles such as envelopes, calling cards, IBM cards, order blanks, installment payment card records, and other similar flat articles, which are desired to be bound collectively but removed intact, without tearing or mutilation.
In view of the foregoing, publications in the art of paper and sheets binding disclose various methods and techniques of reducing tearing and mutilation of the edges of detached sheets. Therefore any improvements to such methods of reducing tearing and mutilation shall entail a utilitarian benefit.
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown merely by way of example in the drawings. The drawings are not necessarily complete and components are not essentially to scale; emphasis instead being placed upon clearly illustrating the principles underlying the present invention.